syzbot

INFO: task syz-executor:6227 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22504 pid:6227  tgid:6227  ppid:1      task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153
 __flush_work+0xa17/0xc50 kernel/workqueue.c:4328
 gfs2_clear_rgrpd+0x117/0x740 fs/gfs2/rgrp.c:731
 gfs2_put_super+0x7d1/0x860 fs/gfs2/super.c:637
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff75ad9da57
RSP: 002b:00007ffce6073748 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007ff75ae32048 RCX: 00007ff75ad9da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffce6073800
RBP: 00007ffce6073800 R08: 00007ffce6074800 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffce6074890
R13: 00007ff75ae32048 R14: 000000000007d5a7 R15: 00007ffce60748d0
 </TASK>
INFO: task kworker/0:2H:6512 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2H    state:D stack:26848 pid:6512  tgid:6512  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: gfs2-glock/syz:syz glock_work_func
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7008
 io_schedule+0x7f/0xd0 kernel/sched/core.c:7835
 bit_wait_io+0x11/0xd0 kernel/sched/wait_bit.c:250
 __wait_on_bit_lock+0xec/0x4e0 kernel/sched/wait_bit.c:93
 out_of_line_wait_on_bit_lock+0x13b/0x190 kernel/sched/wait_bit.c:120
 wait_on_bit_lock_io include/linux/wait_bit.h:221 [inline]
 __lock_buffer fs/buffer.c:72 [inline]
 lock_buffer include/linux/buffer_head.h:432 [inline]
 discard_buffer fs/buffer.c:1603 [inline]
 block_invalidate_folio+0x370/0x730 fs/buffer.c:1660
 folio_invalidate mm/truncate.c:140 [inline]
 truncate_cleanup_folio+0xcb/0x190 mm/truncate.c:160
 truncate_inode_pages_range+0x2ce/0xe30 mm/truncate.c:404
 do_xmote+0x289/0x760 fs/gfs2/glock.c:699
 glock_work_func+0x2a8/0x580 fs/gfs2/glock.c:1011
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e75e5e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:3/49:
2 locks held by getty/5575:
 #0: ffff8880373e90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/6227:
 #0: ffff888030c2e0e0 (&type->s_umount_key#111){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888030c2e0e0 (&type->s_umount_key#111){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888030c2e0e0 (&type->s_umount_key#111){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
2 locks held by kworker/0:2H/6512:
 #0: ffff88805f6b2948 ((wq_completion)gfs2-glock/syz:syz){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #0: ffff88805f6b2948 ((wq_completion)gfs2-glock/syz:syz){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
 #1: ffffc900038b7c40 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
 #1: ffffc900038b7c40 ((work_completion)(&(&gl->gl_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
1 lock held by syz-executor/8122:
 #0: ffffffff8e7648f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #0: ffffffff8e7648f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961
6 locks held by cmp/12304:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5972 Comm: kworker/0:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: rcu_gp process_srcu
RIP: 0010:get_lock_parent_ip include/linux/ftrace.h:1168 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5747 [inline]
RIP: 0010:preempt_count_add+0x93/0x190 kernel/sched/core.c:5772
Code: 11 0f b6 c0 3d f5 00 00 00 73 5d 65 8b 05 95 d2 88 11 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 af 2a 0e 00 85 c0 <74> 09 31 db 31 ff e8 a2 2a 0e 00 65 4c 8b 35 42 d2 88 11 49 81 c6
RSP: 0018:ffffc90002ff78e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8bae33b5 RCX: ffffffff9a282400
RDX: 0000000000000183 RSI: ffffffff8c27d4e0 RDI: ffffffff8bae33b5
RBP: 0000000000000000 R08: ffff8880b8742a97 R09: 1ffff110170e8552
R10: dffffc0000000000 R11: ffffffff8bae3350 R12: 0000000000000001
R13: 000000000000f6dd R14: 0000018346329add R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125454000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558222316048 CR3: 0000000036e49000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 delay_tsc+0x65/0xc0 arch/x86/lib/delay.c:79
 udelay include/asm-generic/delay.h:64 [inline]
 try_check_zero+0x44b/0x4d0 kernel/rcu/srcutree.c:1160
 srcu_advance_state kernel/rcu/srcutree.c:1864 [inline]
 process_srcu+0x31d/0x1630 kernel/rcu/srcutree.c:1973
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>